i) Field of Invention
This application generally relates cognitive radar and radio (RF) technologies, and more particularly, to spectrum sensing processing for rapidly monitoring the RF spectrum for channel availability and activity.
ii) Description of Related Art
It is desirable that RF systems operate without interfering with one other. Cognitive radar/radio systems can be configured dynamically so as to use the best channels in its vicinity to minimize interference. Spectrum sensing is a technique employed by cognitive radio and radar to monitor the RF spectrum for channel availability and the activity of the primary user, i.e. the licensed user. It is a highly valued asset to increase spectrum utilization for cognitive radar and radio. Spectrum utilization is a key issue for radars and radios due to “cluttered” electromagnetic environments (EME), i.e., a growing problem for ground-based and airborne radar systems that need to operate simultaneously without interfering with other radar, communication and electronic warfare systems.
Several known multiband energy detection techniques exist for spectrum sensing include: 1) strategies to reduce computational complexity and minimize spectral leakage; and 2) multiband joint detection techniques that simultaneously detect signal energy over multiple non-overlapping channels. These techniques, however, only consider the energy at a single frequency and do not consider the surrounding energy near a frequency.
This problem is becoming more critical as the frequency spectrum available for radars and radios shrinks due to growing wireless communication device usage and spectrum management regulations And this problem is further exacerbated for radar by the growing number of targets of interest (TOI), whose radar response can vary greatly with frequency; radars thus must adapt to these TOIs while utilizing unoccupied frequency bands.